The use of calcium cyanamide as a pre-plant/emergence treatment of soil dates back approximately one hundred years. For the most part, it has been topically applied as an insoluble, dry nitrogen fertilizer having some pesticidal qualities dependent on latent or applied moisture conditions. There are prior art publications recommending high rates of application, 200 pounds to 2000+ pounds per acre, to reduce crop competitive plants, weed seeds, soil animals and microorganisms. Calcium cyanamide has long been recognized as a nitrogen fertilizer having both fertilizing and pest control effects. At those rates its pest control uses have, for economic and practical reasons, disappeared in the United States in favor of select pesticides.
Contrary to calcium cyanamide, many of today's commonly used nitrogen fertilizers are immediately water soluble and they or their normal metabolites are directly plant leaf and root absorbable. These nitrogen fertilizers, or their metabolites, have been shown to create areas detrimental to plants, seeds, animals and microorganisms that are competitive to commercial crops. Also, certain caustic fertilizers described hereinafter do likewise. These products alone, however, have not been satisfactorily perfected as plant protectants.
Recommendations for applying calcium cyanamide fertilizer at levels below 200 pounds per acre have not heretofore been recommended. As an example of the effectiveness of the processes taught herein, the prior art teaches a 41% nematode reduction using 427 pounds per acre of calcium cyanamide in "ideal wet" soil versus an 86% reduction resulted using only 20 pounds per acre when the processes described herein are followed.
For various reasons, the use of calcium cyanamide as a dry nitrogen fertilizer treatment has dropped dramatically in United States agriculture in favor of soluble nitrogen fertilizers. These reasons include calcium cyanamide's comparative high energy dependent unit cost. A second reason is its historically high-rate biocidal cost compared to recently developed pesticides. Thirdly, its dry, dusty noxious fines makeup is undesirable for human handling and difficult to measure and calibrate alone or with other fertilizers for maximum effectiveness. A higher cost, lower analysis pelletized form improves, but does not eliminate, direct dry application handling problems. Fourth, several of calcium cyanamide soil beneficial components, namely calcium and carbon, will clog standard liquid spray applicators if one attempts to dissolve it in water for efficient dispersal.